Tricyclic angiotensin II agonists

ABSTRACT

There is provided compounds of formula I, 
                         
wherein the dotted line, X 1 , X 2 , X 3 , A, Y 1 , Y 2 , Y 3 , Y 4 , Z 1 , Z 2 , R 2  and R 3  have meanings given in the description, and pharmaceutically-acceptable salts thereof, which compounds are useful as selective agonists of the AT2 receptor, and thus, in particular, in the treatment of inter alia gastrointestinal conditions, such as dyspepsia, IBS and MOF, and cardiovascular disorders.

This application is the U.S. National Phase of International Application PCT/GB2006/001332, filed 12 Apr. 2006, which designated the U.S. PCT/GB2006/001332 claims priority to U.S. Provisional Application No. 60/670,257, filed 12 Apr. 2005. The entire content of these applications are incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to novel pharmaceutically-useful compounds, in particular compounds that are angiotensin II (AngII) agonists, more particularly agonists of the AngII type 2 receptor (hereinafter the AT2 receptor), and especially agonists that bind selectively to that receptor. The invention further relates to the use of such compounds as medicaments, to pharmaceutical compositions containing them, and to synthetic routes to their production.

BACKGROUND AND PRIOR ART

The endogenous hormone AngII is a linear octapeptide (Asp¹-Arg²-Val³-Tyr⁴-Ile⁵-His⁶-Pro⁷-Phe⁸), and is the active component of the renin-angiotensin system (RAS). It is produced by the sequential processing of the pro-hormone angiotensinogen by renin and angiotensin converting enzyme (ACE).

The renin-angiotensin system (RAS) plays an important role in the regulation of blood pressure, body fluid and electrolyte homeostasis. Ang II exerts these physiological actions in many organs including the kidneys, the adrenal glands, the heart, blood vessels, the brain, the gastrointestinal tract and the reproductive organs (de Gasparo et al, Pharmacol. Rev. (2000) 52, 415-472).

Two main classes of AngII receptors have been identified, and designated as the type 1 receptor (hereinafter the AT1 receptor) and the AT2 receptor. The AT1 receptor is expressed in most organs, and is believed to be responsible for the majority of the biological effects of AngII. The AT2 receptor is more prevalent than the AT1 receptor in fetal tissues, the adult ovaries, the adrenal medulla and the pancreas. An equal distribution is reported in the brain and uterus (Ardaillou, J. Am. Soc. Nephrol., 10, S30-39 (1999)).

Several studies in adult individuals appear to demonstrate that, in the modulation of the response following AngII stimulation, activation of the AT2 receptor has opposing effects to those mediated by the AT1 receptor.

The AT2 receptor has also been shown to be involved in apoptosis and inhibition of cell proliferation (see de Gasparo et al, supra). Further, it seems to play a role in blood pressure control. For example, it has been shown in transgenic mice lacking AT2 receptors that their blood pressure was elevated. Furthermore, it has been concluded that the AT2 receptor is involved in exploratory behaviour, pain sensitivity and thermoregulation.

The expression of AT2 receptors has also been shown to increase during pathological circumstances, such as vascular injury, wound healing and heart failure (see de Gasparo et al, supra).

The expected pharmacological effects of agonism of the AT2 receptor are described generally in de Gasparo et al, supra.

More recently, AT2 receptor agonists have been shown to be of potential utility in the treatment and/or prophylaxis of disorders of the alimentary tract, such as dyspepsia and irritable bowel syndrome, as well as multiple organ failure (see international patent application WO 99/43339).

AngII antagonists (which bind to the AT1 and/or AT2 receptors) have been disclosed in inter alia international applications WO 93/04045, WO 93/04046, WO 94/11379 and WO 94/28896, U.S. Pat. Nos. 5,312,820 and 5,512,681, European patent applications EP 0 499 415, EP 399 731 and EP 399 732, Pandya et al, Bioorganic & Medicinal Chemistry, 9, 291-300 (2001) and Chang et al, Bioorganic & Medicinal Chemistry Letters, 4, 2787-2792 (1994). The use of the compounds disclosed in these documents as agonists of AngII, and in particular the AT2 receptor, is not contemplated.

U.S. Pat. No. 5,444,067 discloses compounds comprising an imidazolyl group attached, via a methylene bridge, to a phenylthiophene moiety, as AngII agonists. The phenyl ring of the phenylthiophene moiety in these molecules is 1,4-disubstituted with the thiophene and the imidazolyl group (which is attached via a methylene bridge).

More recently, international patent applications WO 02/96883, WO 03/064414, WO 2004/085420, WO 2004/046128, WO 2004/046141 and WO 2004/046137 have disclosed various multicyclic compounds as agonists of AngII and in particular as selective AT2 receptor agonists. In the compounds disclosed in these documents, a central aryl ring is disubstituted in the 1,4 (para) configuration. None of these documents mention or suggest compounds in which such an aryl group is disubstituted in the 1,3 (meta) configuration.

We have now found that such compounds are effective and/or selective AT2 receptor agonists and are therefore expected to find utility in inter alia the above-mentioned conditions.

DISCLOSURE OF THE INVENTION

According to the invention there is provided a compound of formula I,

wherein X₁ represents —C(R^(1a))(R^(1b))—, —N(R^(1a))— or —O—; the dotted line signifies an optional double bond; and in the case when the dotted line does not signify a double bond, X₂ and X₃ independently represent —C(R^(1c))(R^(1d))—, —N(R^(1e))—, —O—, —C(O)— or —C(R^(1f))(R^(1g))—C(R^(1h))(R^(1j))— provided that:

-   (i) when X₁ represents —N(R^(1a))—, then X₂ and X₃ do not both     represent N(R^(1e))—; -   (ii) when X₁ represents —O—, then X₂ and X₃ do not both represent     —O—; -   (iii) when X₁ represents —O— and X₂ represents —N(R^(1e)—, then X₃     represents —C(O)—; and -   (iv) when X₁ represents —O— and X₃ represents —N(R^(1e))—, then X₂     does not represent —C(R^(1c))(R^(1d))—; or     in the case when the dotted lines signifies a double bond, X² and X³     independently represent —N— or —C(R^(1c))—;     R^(1a), R^(1b), R^(1c), R^(1e), R^(1f), R^(1g), R^(1h) and R^(1j)     independently represent H, C₁₋₆ alkyl, C₁₋₆ alkoxy, C₁₋₆ alkoxy-C₁₋₆     alkyl, Ar¹, Het¹, C₁₋₃ alkyl-Ar², C₁₋₃ alkyl-Het², C₁₋₃ alkoxy-Ar³,     C₁₋₃ alkoxy-Het³, halo, —C(O)—C₁₋₆ alkyl, —C(O)—Ar⁴ or —C(O)—Het⁴;     Ar¹, Ar², Ar³ and Ar⁴ each independently represent a C₆₋₁₀ aryl     group, which group is optionally substituted by one or more     substituents selected from ═O, —OH, cyano, halo, nitro, C₁₋₆ alkyl     (optionally terminated by —N(H)C(O)OR^(11a)), C₁₋₆ alkoxy, phenyl,     —N(R^(12a))R^(12b), —C(O)R^(12c), —C(O)OR^(12d),     —C(O)N(R^(12e))R^(12f), —N(R^(12g))C(O)R^(12h),     —N(R^(12i))C(O)N(R^(12j))R^(12k), —N(R^(12m))S(O)₂R^(11b),     —S(O)_(p)R^(11c), —OS(O)₂R^(11d) and —S(O)₂N(R^(12n))R^(12p);     Het¹, Het², Het³ and Het⁴ each independently represent a four- to     twelve-membered heterocyclic group containing one or more     heteroatoms selected from oxygen, nitrogen and/or sulfur, which     heterocyclic group is optionally substituted by one or more     substituents selected from ═O, —OH, cyano, halo, nitro, C₁₋₆ alkyl     (optionally terminated by —N(H)C(O)OR^(11a)), C₁₋₆ alkoxy, phenyl,     —N(R^(12a))R^(12b), —C(O)R^(12c), —C(O)OR^(12d),     —C(O)N(R^(12e))R^(12f), —N(R^(12g))C(O)R^(12h),     —N(R^(12i))C(O)N(R^(12j))R^(12k), —N(R^(12m))S(O)₂R^(11b),     —S(O)_(p)R^(11c), —OS(O)₂R^(11d) and —S(O)₂N(R^(12n))R^(12p);     R^(11a) to R^(11d) independently represent, on each occasion when     used herein, C₁₋₆ alkyl;     R^(12a) to R^(12p) independently represent, on each occasion when     used herein, H or C₁₋₆ alkyl;     p represents 0, 1 or 2;     A represents —C(O) or —CH₂—;     Y₁, Y₂, Y₃ and Y₄ independently represent —CH— or —CF—;     Z₁ represents —CH—, —O—, —S—, —N— or —CH═CH—;     Z₂ represents —CH—, —O—, —S— or —N—;     provided that: -   (a) Z₁ and Z₂ are not the same; -   (b) when Z₁ represents —CH═CH—, then Z₂ may only represent —CH— or     —N—; and -   (c) other than in the specific case in which Z₁ represents —CH═CH—,     and Z₂ represents —CH—, when one Z₁ and Z₂ represents —CH—, then the     other represents —O— or —S—;     R² represents —S(O)₂N(H)C(O)R⁴, —S(O)₂N(H)S(O)₂R⁴, —C(O)N(H)S(O)₂R⁴,     or, when Z₁ represents —CH═CH—, R² may represent     —N(H)S(O)₂N(H)C(O)R⁵ or —N(H)C(O)N(H)S(O)₂R⁵;     R³ represents C₁₋₆ alkyl, C₁₋₆ alkoxy, C₁₋₆ alkoxy-C₁₋₆-alkyl or     di-C₁₋₃-alkylamino-C₁₋₄-alkyl;     R⁴ represents C₁₋₆ alkyl, C₁₋₆ alkoxy, C₁₋₆ alkoxy-C₁₋₆-alkyl, C₁₋₃     alkoxy-C₁₋₆-alkoxy, C₁₋₆ alkylamino or di-C₁₋₆ alkylamino; and     R⁵ represents C₁₋₆ alkyl,     or a pharmaceutically-acceptable salt thereof,     which compounds and salts are referred to together hereinafter as     “the compounds of the invention”.

Pharmaceutically-acceptable salts include acid addition salts and base addition salts. Such salts may be formed by conventional means, for example by reaction of a free acid or a free base form of a compound of the invention with one or more equivalents of an appropriate acid or base, optionally in a solvent, or in a medium in which the salt is insoluble, followed by removal of said solvent, or said medium, using standard techniques (e.g. in vacuo or by freeze-drying). Salts may also be prepared by exchanging a counter-ion of a compound of the invention in the form of a salt with another counter-ion, for example using a suitable ion exchange resin.

Unless otherwise specified, alkyl groups, and the alkyl parts of alkoxy, alkoxyalkyl, alkoxyalkoxy, alkylamino, alkylaminoalkyl, alkyl-aryl, alkyl-heterocyclic groups, alkoxy-aryl and alkoxy-heterocyclic groups, as defined herein may be straight-chain or, when there is a sufficient number (i.e. a minimum of two or three, as appropriate) of carbon atoms, be branched-chain, and/or cyclic. Further, when there is a sufficient number (i.e. a minimum of four) of carbon atoms, such groups may also be part cyclic/acyclic. Such alkyl groups, and alkyl parts of alkoxy, alkoxyalkyl, alkoxyalkoxy, alkylamino, alkylaminoalkyl, alkyl-aryl, alkyl-heterocyclic, alkoxy-aryl and alkoxy-heterocyclic groups may also be saturated or, when there is a sufficient number (i.e. a minimum of two) of carbon atoms, be unsaturated. Unless otherwise specified, such groups may also be substituted by one or more halo, and especially fluoro, atoms.

For the avoidance of doubt, alkoxy and alkoxyalkoxy groups are attached to the rest of the molecule via the/an oxygen atom in that group, alkylamino groups are attached to the rest of the molecule via the nitrogen atom of the amino part of that group, alkoxyalkyl, alkylaminoalkyl, alkyl-aryl and alkyl-heterocyclic groups are attached to the rest of the molecule via the alkyl part of that group, and alkoxy-aryl and alkoxy-heterocyclic groups are attached to the rest of the molecule via the alkyl part of the alkoxy part of that group.

The term “halo”, when used herein, includes fluoro, chloro, bromo and iodo.

For the avoidance of doubt, in cases in which the identity of two or more substituents in a compound of the invention (for example any two or more of the substituents R^(1a) to R^(1j)) may be the same, the actual identities of the respective substituents are not in any way interdependent. For example, in the situation in which two or more of R^(1a) to R^(1j) represent C₁₋₆ alkyl groups, the alkyl groups in question may be the same or different. Similarly, when aryl and heterocyclic groups are substituted by more than one substituent as defined herein, the identities of the individual substituents are not to be regarded as being interdependent.

C₆₋₁₀ aryl groups include phenyl, naphthyl and the like (preferably phenyl). Preferred optional substituents on aromatic groups include halo, —OH, cyano, nitro, C₁₋₆ (e.g. C₁₋₃) alkoxy groups and, more particularly, C₁₋₆ (e.g. C₁₋₃) alkyl groups (such as methyl).

Het (Het¹, Het², Het³ and Het⁴) groups that may be mentioned include those containing 1 to 4 heteroatoms (selected from the group oxygen, nitrogen and/or sulfur) and in which the total number of atoms in the ring system are between five and twelve. Het (Het¹, Het², Het³ and Het⁴) groups may be fully saturated, wholly aromatic, partly aromatic and/or bicyclic in character. Heterocyclic groups that may be mentioned include benzodioxanyl, benzodioxepanyl, benzodioxolyl, benzofuranyl, benzofurazanyl, benzimidazolyl, benzomorpholinyl, benzothiophenyl, chromanyl, cinnolinyl, dioxanyl, furanyl, hydantoinyl, imidazolyl, imidazo[1,2-a]pyridinyl, indolyl, isoquinolinyl, isoxazolyl, maleimido, morpholinyl, oxazolyl, phthalazinyl, piperazinyl, piperidinyl, purinyl, pyranyl, pyrazinyl, pyrazolyl, pyridinyl, pyrimindinyl, pyrrolidinonyl, pyrrolidinyl, pyrrolinyl, pyrrolyl, quinazolinyl, quinolinyl, 3-sulfolenyl, tetrahydropyranyl, tetrahydrofuranyl, thiazolyl, thiophenyl, thiochromanyl, triazolyl, tetrazolyl and the like. Values of Het¹ that may be mentioned include thiophenyl, furanyl, pyridinyl and thiazolyl. Values of Het² that may be mentioned include pyridinyl, furanyl, thiophenyl and thiazolyl. Values of Het³ and Het⁴ that may be mentioned include pyridinyl.

Substituents on Het (Het¹, Het², Het³ and Het⁴) groups may, where appropriate, be located on any atom in the ring system including a heteroatom. The point of attachment of Het (Het¹, Het², Het³ and Het⁴) groups may be via any atom in the ring system including (where appropriate) a heteroatom, or an atom on any fused carbocyclic ring that may be present as part of the ring system. Het (Het¹, Het², Het³ and Het⁴) groups may also be in the N- or S-oxidised form.

Preferred ring systems comprising the substituents Y₁, Y₂, Y₃ and Y₄ include phenyl groups. For the avoidance of doubt, the ring systems in compounds of formula I that comprise the groups Z₁ and Z₂, are aromatic in nature. In some instances, for example in cases where one of Z₁ and Z₂ represents —N—, the skilled person will appreciate that an additional H atom may necessarily be bonded to that N atom, in order to ensure that the rules of valency are adhered to. Preferred ring systems comprising Z₁ and Z₂ include oxazole groups, thiazole groups, pyridinyl groups, furanyl groups and, more particularly, thiophenyl groups and phenyl groups.

In this respect, compounds of the invention may exhibit tautomerism. All tautomeric forms and mixtures thereof are included within the scope of the invention.

Compounds of the invention also contain one or more asymmetric carbon atoms and may therefore exhibit optical and/or diastereoisomerism. Diastereoisomers may be separated using conventional techniques, e.g. chromatography or fractional crystallisation. The various stereoisomers may be isolated by separation of a racemic or other mixture of the compounds using conventional, e.g. fractional crystallisation or HPLC, techniques. Alternatively the desired optical isomers may be made by reaction of the appropriate optically active starting materials under conditions which will not cause racemisation or epimerisation, or by derivatisation, for example with a homochiral acid followed by separation of the diastereomeric derivatives by conventional means (e.g. HPLC, chromatography over silica). All stereoisomers are included within the scope of the invention.

Compounds of the invention that may be mentioned include those in which, when Z₁ represents —CH═CH—, Z₂ represents —CH—, R² represents —S(O)₂N(H)C(O)R⁴, R³ represents n-propyl, Y₁, Y₂ and Y₃ all represent —CH—, A represents —CH₂—, the dotted line signifies a double bond, X₁ represents —N(R^(1a))—, X₂ represents —N—, X₃ represents —C(R^(1c))— and R^(1c) represents n-butyl, then:

-   (a) when Y₄ represents —CF— and R^(1a) represents a     2-chloro,5-acetamidophenyl group, then R⁴ does not represent     t-butoxy or ethoxy; and -   (b) when Y₄ represents —CH— and R^(1a) represents a     2-trifluoromethylphenyl group, then R⁴ does not represent t-butoxy.

Further compounds of the invention that may be mentioned include those in which:

-   (i) R^(1c) represents C₁₋₃ alkyl, C₅₋₆ alkyl or, more preferably, H,     C₁₋₆ alkoxy, C₁₋₆ alkoxy-C₁₋₆ alkyl, Ar¹, Het¹, C₁₋₃ alkyl-Ar², C₁₋₃     alkyl-Het², C₁₋₃ alkoxy-Ar³, C₁₋₃ alkoxy-Het³, halo, —C(O)—C₁₋₆     alkyl, —C(O)—Ar⁴ or —C(O)-Het⁴; -   (ii) R^(1c) does not represent n-butyl; or -   (iii) R^(1c) represents H.

Preferred compounds of the invention include those in which:

the dotted line does not signify a double bond;

X₁ represents —C(R^(1a))(R^(1b))— or —N(R^(1a))—;

X₂ represents —O—, —N(R^(1e))— or, more preferably, —C(R^(1c))(R^(1d))—;

X₃ represents —O—, —C(R^(1f))(R^(1g))—C(R^(1h))(R^(1j))— or, more preferably, —C(R^(1c))(R^(1d))— or —C(O)—;

R^(1a) represents H or C₁₋₃ alkyl, such as methyl;

R^(1b) represents C₁₋₃ alkyl, such as methyl, or, especially, H;

R^(1c) represents C₁₋₃ alkyl, such as methyl, or, especially, H;

R^(1d) represents C₁₋₃ alkyl, such as methyl, or, especially, H.

More preferred compounds of the invention include those in which:

X₁ represents —CH₂— or —N(CH₃)—;

X₂ represents —CH₂—;

X₃ represents —CH₂— or —C(O)—;

A represents —CH₂—;

Y₁, Y₂, Y₃ and Y₄ all represent —CH—;

Z₁ represents —CH═CH— or, especially, —S—;

Z₂ represents —CH—;

R² represents —S(O)₂N(H)C(O)R⁴;

R³ represents C₁₋₄ alkyl such as n-butyl or, particularly, iso-butyl;

R⁴ represents C₁₋₄ alkoxy-C₁₋₃ alkyl or C₁₋₄ alkoxy (such as n-butoxymethyl, iso-butoxy and, especially, n-butoxy).

When R² represents —S(O)₂N(H)C(O)R⁴, —S(O)₂N(H)S(O)₂R⁴ or —C(O)N(H)S(O)₂R⁴, preferred values of R⁴ include n-butoxymethyl, iso-butoxy and especially, n-butoxy.

Preferred ring systems comprising the groups X₁, X₂ and X₃ include optionally substituted 2-pyrrolidinon-1-yl groups, 2,5-pyrrolidindion-1-yl and hydantoin-3-yl groups. Preferred optional substituents include C₁₋₃ alkyl (e.g. methyl).

More preferred compounds of the invention include the compounds of the examples described hereinafter.

Compounds of formula I may be made in accordance with techniques well known to those skilled in the art, for example as described hereinafter.

According to a further aspect of the invention there is provided a process for the preparation of a compound of formula I, which process comprises:

(i) for compounds of formula I in which R² represents —S(O)₂N(H)C(O)R⁴ or —S(O)₂N(H)S(O)₂R⁴, and R⁴ is as hereinbefore defined, reaction of a compound of formula II,

wherein the dotted line, X₁, X₂, X₃, A, Y₁, Y₂, Y₃, Y₄, Z₁, Z₂ and R³ are as hereinbefore defined with a compound of formula III, R⁴GL¹  III wherein G represents —C(O)— or —S(O)₂— (as appropriate), L¹ represents a suitable leaving group, such as halo (e.g. chloro or bromo) and R⁴ is as hereinbefore defined, for example at around room temperature or above (e.g. up to 60-70° C.) in the presence of a suitable base (e.g. pyrrolidinopyridine, pyridine, triethylamine, tributylamine, trimethylamine, dimethylaminopyridine, di-iso-propylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene, sodium hydroxide, sodium carbonate, or mixtures thereof) and an appropriate solvent (e.g. pyridine, dichloromethane, chloroform, tetrahydrofuran, dimethylformamide, trifluoromethylbenzene, triethylamine, water, or mixtures thereof). Preferred base/solvent systems for compounds of formula III in which G is —C(O)— include pyrrolidinopyridine/pyridine, pyrrolidinopyridine/triethylamine, dimethylaminopyridine/pyridine, dimethyl-aminopyridine/triethylamine, sodium carbonate/dichloromethane/water or pyrrolidinopyridine/triethylamine/dichloromethane. Preferred base/solvent systems for compounds of formula III in which G is —S(O)₂— include NaOH/THF; (ii) for compounds of formula I in which R² represents —S(O)₂N(H)C(O)R⁴ and R⁴ represents C₁₋₆ alkoxy-C₁₋₆-alkyl, coupling of a compound of formula II as hereinbefore defined with a compound of formula IV, R^(4a)CO₂H  IV wherein R^(4a) represents C₁₋₆ alkoxy-C₁₋₆-alkyl, for example under similar conditions to those described under process step (i) above, in the presence of a suitable coupling reagent (e.g. 1,1′-carbonyl-diimidazole, N,N′-dicyclohexylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N,N′-disuccinimidyl carbonate, benzotriazole-1-yloxytris(dimethylamino)phosphoniumhexafluorophosphate, 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate, benzotriazole-1-yl-oxy-tris-pyrrolidino-phosphonium hexafluorophosphate, bromo-tris-pyrrolidinophosphonium hexafluorophosphate or 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluorocarbonate), a suitable base (as mentioned in process step (i) above) and an appropriate solvent (as mentioned in process step (i) above); (iii) for compounds of formula I in which R² represents —C(O)N(H)S(O)₂R⁴ and R⁴ is as hereinbefore defined, coupling of a compound of formula V,

wherein the dotted line, X₁, X₂, X₃, A, Y₁, Y₂, Y₃, Y₄, Z₁, Z₂ and R³ are as hereinbefore defined with a compound of formula VI, R⁴S(O)₂NH₂  VI wherein R⁴ is as hereinbefore defined, for example in the presence of a suitable coupling reagent (such as those described in process step (ii) hereinbefore), and under similar reaction conditions to those described hereinbefore for preparation of compounds of formula I in which R² represents —S(O)₂N(H)C(O)R⁴ and R⁴ represents C₁₋₆ alkoxy-C₁₋₆-alkyl (i.e. process step (ii)); (iv) for compounds of formula I in which R² represents —C(O)N(H)S(O)₂R⁴ and R⁴ is as hereinbefore defined, coupling of a compound of formula VII,

wherein the dotted line, X₁, X₂, X₃, A, Y₁, Y₂, Y₃, Y₄, Z₁, Z₂ and R³ are as hereinbefore defined with a compound of formula VIII, R⁴S(O)₂Cl  VIII wherein R⁴ is as hereinbefore defined, for example at around 50° C. in the presence of a suitable base (e.g. sodium hydride) and an appropriate organic solvent (e.g. THF); (v) for compounds of formula I in which R² represents —N(H)S(O)₂N(H)C(O)R⁵ and R⁵ is as hereinbefore defined, reaction of a compound of formula IX,

wherein the dotted line, X₁, X₂, X₃, A, Y₁, Y₂, Y₃, Y₄, Z₁, Z₂ and R³ are as hereinbefore defined with a compound of formula X, R⁵C(O)N(H)S(O)₂Cl  X wherein R⁵ is as hereinbefore defined, for example at or around room temperature in the presence of a suitable base (e.g. sodium hydroxide or triethylamine) and a suitable organic solvent (e.g. benzene or dichloromethane); (vi) for compounds of formula I in which R² represents —N(H)C(O)N(H)S(O)₂R⁵ and R⁵ is as hereinbefore defined, reaction of a compound of formula IX as hereinbefore defined with a compound of formula XI, R⁵S(O)₂N(H)C(O)R^(x)  XI wherein R^(x) represents a suitable leaving group, such as a halo (e.g. chloro or bromo) group or alkoxy (e.g. —O—C₁₋₂ alkyl) and R⁵ is as hereinbefore defined, for example at or around room temperature in the presence of a suitable organic solvent (e.g. dichloromethane). Alternatively R^(x) may represent —OH, in which case the coupling reaction may be performed under conditions such as those hereinbefore described in respect of process (ii) above; (vii) for compounds of formula I in which R² represents —N(H)C(O)N(H)S(O)₂R⁵ and R⁵ is as hereinbefore defined, reaction of a compound of formula IX as hereinbefore defined with an isocyanate compound of formula XII, R⁵S(O)₂NCO  XII wherein R⁵ is as hereinbefore defined, for example at or around room temperature in the presence of a suitable organic solvent (e.g. dichloromethane); (viii) for compounds of formula I in which R² represents —S(O)₂N(H)C(O)R⁴ and R⁴ represents C₁₋₆ alkylamino, reaction of a compound of formula II as hereinbefore defined with an isocyanate compound of formula XIII, R^(4b)NCO  XIII wherein R^(4b) is C₁₋₆ alkyl, for example at or around room temperature in the presence of a suitable base (e.g. sodium hydroxide or potassium hydroxide and an appropriate organic solvent (e.g. acetone or acetonitrile); or (ix) for compounds of formula I in which R² represents —S(O)₂N(H)C(O)R⁴ and R⁴ represents di-C₁₋₆ alkylamino, reaction of a corresponding compound of formula I in which R² represents —S(O)₂N(H)C(O)R⁴ and R⁴ represents C₁₋₆ alkoxy with a compound of formula XIV, R^(4c)N(H)R^(4d)  XIV wherein R^(4c) and R^(4d) independently represent C₁₋₆ alkyl, for example at above room temperature (e.g. at between 70° C. and 100° C.) in the presence of an appropriate organic solvent (e.g. toluene).

Compounds of formula V may be prepared by oxidation of a compound of formula XV,

wherein the dotted line, X₁, X₂, X₃, A, Y₁, Y₂, Y₃, Y₄, Z₁, Z₂ and R³ are as hereinbefore defined, for example under standard oxidation conditions in the presence of a suitable oxidising agent, such as potassium permanganate or chromium (VI) oxide.

Compounds of formulae II, VII, IX and XV may be prepared by reaction of a compound of formula XVI,

wherein R^(y) represents —SO₂NH₂ (in the case of a compound of formula II), —CONH₂ (in the case of a compound of formula VII), —NH₂ (in the case of a compound of formula IX), or —CHO (in the case of a compound of formula XV) and R³, Z₁ and Z₂ are as hereinbefore defined, or a protected derivative thereof, with a compound of formula XVII,

wherein L² represents a suitable leaving group, such as methylsulphonate (e.g. trifluoromethylsulphonate), or halo, such as iodo or bromo, and the dotted line, X₁, X₂, X₃, A, Y₁, Y₂, Y₃ and Y₄ are as hereinbefore defined, for example in the presence of an appropriate coupling catalyst system (e.g. a palladium catalyst, such as Pd(PPh₃)₄ or Pd(OAc)₂/ligand (wherein the ligand may be, for example, PPh₃, P(o-Tol)₃ or 1,1′-bis(diphenylphosphino)ferrocene)) and a suitable base (e.g. sodium hydroxide, sodium carbonate, potassium carbonate, cesium carbonate, cesium fluoride, triethylamine or di-iso-propylethylamine), as well as a suitable solvent system (e.g. toluene, ethanol, dimethoxymethane, dimethylformamide, ethylene glycol dimethyl ether, water, dioxane or mixtures thereof). This reaction may be carried out at above room temperature (e.g. at a high temperature, such as the reflux temperature of the solvent system that is employed). Preferably, compounds of formula XVI are protected at the R^(y) position prior to carrying out the reaction with the compound of formula XVII. Suitable protecting groups for different values of R^(y) are described hereinafter. If a protected version of a compound of formula XVI is employed, this reaction may be followed by deprotection of the R^(y) group under standard conditions, for example as described hereinafter.

Compounds of formulae II, VII, IX and XV may alternatively be prepared by reaction of a compound of formula XVIII,

wherein the dotted line, X₁, X₂ and X₃ are as hereinbefore defined with a compound of formula XIX,

wherein A, Y₁, Y₂, Y₃, Y₄, Z₁, Z₂, R^(y), R³ and L¹ are as hereinbefore defined (L¹, in particular, may represent bromo), or a protected (at the R^(y) part) derivative thereof, for example at around, below or, preferably, above room temperature (e.g. at 80° C.), optionally in the presence of a suitable base (e.g. potassium tert-butoxide, potassium hydroxide, sodium hydroxide, sodium carbonate, triethylamine or di-iso-propylethylamine) and an appropriate organic solvent (e.g. DMSO, dioxane, DMF, THF or CH₂Cl₂). In the case where base is not employed, the skilled person will appreciate that at least two equivalents of the compound of formula XVIII may need to be employed. When A represents —CH₂—, suitable bases include potassium hydroxide and potassium tert-butoxide and suitable solvents include DMSO, THF, DMF, dioxane or CH₂Cl₂. When A represents —C(O)—, suitable bases include triethylamine and di-iso-propylethylamine and suitable solvents include DMSO, DMF, THF and CH₂Cl₂. Suitable protecting groups for different values of R^(y) are described hereinafter. If a protected version of a compound of formula XIX is employed, this reaction may be followed by deprotection of the R^(y) group under standard conditions, for example as described hereinafter.

Compounds of formula XVI and protected derivatives thereof may be prepared by reaction of a corresponding compound of formula XX,

wherein R^(y), R³, Z₁ and Z₂ are as hereinbefore defined, or an appropriate protected derivative thereof, with a reagent system that will enable the introduction of the —B(OH)₂ into the appropriate ring system. Suitable reagent systems include trialkylborates (e.g. tri-iso-propylborate). Such reactions may be carried out, for example, at low temperature (e.g. between −100° C. and 0° C., e.g. between −80° C. (such as −78° C.) and −10° C. (such as −20° C.)) in the presence of a suitable base (e.g. n-butyl lithium) and an appropriate organic solvent (e.g. THF), followed by acid hydrolysis (e.g. in the presence of dilute HCl).

Compounds of formula XVII may be prepared by standard techniques, for example by way of reaction of a compound of formula XVIII as hereinbefore defined with a compound of formula XXI,

wherein A, Y₁, Y₂, Y₃, Y₄, L¹ and L² are as hereinbefore defined, for example under similar conditions to those described hereinbefore in respect of preparation of compounds of formulae II, VII, IX and XV (second process).

Compounds of formula XIX may be prepared by analogy with the processes described in inter alia U.S. Pat. No. 5,312,820, UK patent application GB 2281298, and/or by reaction of a compound of formula XVI as hereinbefore defined with a compound of formula XXII,

wherein A, Y₁, Y₂, Y₃, Y₄ and L² are as hereinbefore defined, for example under similar conditions to those described hereinbefore in respect of preparation of compounds of formulae II, VII, IX and XV (first process), followed by conversion of the OH group in the resultant intermediate to an appropriate leaving group, L¹ (e.g., in the case where A is —CH₂— and L¹ is bromo, conversion may be carried out by reaction with CBr₄, for example at or around room temperature in the presence of a base (e.g. triphenylphosphine) and a suitable organic solvent (e.g. DMF). Alternatively, the hydroxyl group may be converted to a sulfonate leaving group (e.g. mesylate or triflate) by employing a suitable reagent (e.g. a sulfonyl halide such as tosyl chloride, mesyl chloride or triflic anhydride); similarly, when A represents —C(O)— and L¹ represents Cl, the intermediate acid may be reacted with SOCl₂ in benzene or toluene, or with oxalyl chloride in DCM).

Compounds of formula XX are available using known techniques. For example:

-   (a) Compounds of formula XX in which R^(y) represents —S(O)₂NH₂,     —C(O)NH₂ or —CHO, and protected derivatives thereof, may be prepared     by reaction of a compound of formula XXIII,

-    wherein R^(ya) represents —S(O)₂NH₂, —C(O)NH₂ or —CHO and Z₁ and Z₂     are as hereinbefore defined, or a protected derivative thereof, with     a compound of formula XXIV,     R³L³  XXIV -    wherein L³ represents a suitable leaving group (such as     toluenesulphonate, benzenesulphonate, methanesulphonate or halo,     such as bromo or iodo) and R³ is as hereinbefore defined, for     example at below room temperature (e.g. between around −35° C. and     around −85° C.), in the presence of a suitable base (e.g. n-butyl     lithium) and an appropriate solvent (e.g. THF). -   (b) Compounds of formula XX in which R^(y) is —S(O)₂NH₂ and     N-protected derivatives thereof, may be prepared by reaction of an     appropriate compound of formula XXV,

-    wherein R³, Z₁ and Z₂ are as hereinbefore defined with an     appropriate reagent for introduction of a —S(O)₂NH₂ group into the     appropriate ring system (for example chlorosulphonic acid, or     thionyl chloride in the presence of a suitable strong base (e.g.     butyl lithium)), followed by reaction of the resultant intermediate     with ammonia, or a protected derivative thereof (e.g.     tert-butylamine), under conditions that are well known to those     skilled in the art. -   (c) Certain protected derivatives (e.g. alkyl, such as C₁₋₆ alkyl,     for example tert-butyl, protected derivatives) of compounds of     formula XX in which R^(y) represents —C(O)NH₂ may be prepared by     reaction of a compound of formula XXV as hereinbefore defined, with     a compound of formula XXVI,     R^(Z)N═C═O  XXVI -    wherein R^(Z) represents an appropriate protecting group, such as     an alkyl group, including C₁₋₆ alkyl, e.g. tert-butyl, for example     at low temperature (e.g. −78° C. to around 0° C.), in the presence     of a suitable base (e.g. n-butyl lithium) and an appropriate solvent     (e.g. THF). -   (d) Certain protected derivatives (e.g. alkyl, such as C₁₋₆ alkyl,     for example tert-butyl, protected derivatives) of compounds of     formula XX in which R^(y) represents —C(O)NH₂ may also be prepared     by reaction of a compound of formula XXVII,

-    wherein R³, Z₁ and Z₂ are as hereinbefore defined with a protected     (e.g. an (e.g. C₁₋₆) alkyl, such as tert-butyl-protected) derivative     of ammonia (e.g. tert-butylamine) under standard coupling conditions     (see, for example, those described hereinbefore for preparation of     compounds of formula I (process step (iii))). Compounds of formula     XXVII are known in the art or may be prepared by way of standard     techniques, for example oxidation of a corresponding compound of     formula XX in which R^(y) is —CHO e.g. under those conditions     described hereinbefore for preparation of compounds of formula V. -   (e) Compounds of formula XX in which R^(y) is —CHO, Z₁ represents     —CH═CH— and Z₂ represents —CH—, and protected derivatives thereof,     may be prepared by reaction of a compound of formula XXV in which Z₁     represents —CH═CH— and Z₂ represents —CH— with an appropriate     reagent system for the introduction of an aldehyde group into the     benzene ring (e.g. Zn(CN)₂ and HCl or, preferably, TiCl₄/CHCl₃,     SnCl₄/CH₂Cl₂ or 1,3,5,7-azaadamantane/TFA) under standard reaction     conditions, followed by (if appropriate) protection of the resultant     benzaldehyde under standard conditions. -   (f) Compounds of formula XX in which R^(y) is —NH₂, Z₁ represents     —CH═CH— and Z₂ represents —CH—, and N-protected derivatives thereof,     may be prepared by nitration of a compound of formula XXV in which     Z₁ represents —CH═CH— and Z₂ represents —CH—, followed by reduction     of the resultant nitrobenzene and (if appropriate) protection of the     resultant aminobenzene, all of which steps may be carried out under     standard conditions.

Compounds of formulae III, IV, VI, VIII, X, XI, XII, XIII, XIV, XVIII, XXI, XXII, XXIII, XXIV, XXV, XXVI and XXVII are either commercially available, are known in the literature, or may be obtained either by analogy with the processes described herein, or by conventional synthetic procedures, in accordance with standard techniques, from readily available starting materials using appropriate reagents and reaction conditions.

Compounds of the invention may be isolated from their reaction mixtures using conventional techniques.

It will be appreciated by those skilled in the art that, in the processes described above and hereinafter, the functional groups of intermediate compounds may need to be protected by protecting groups.

Functional groups that it is desirable to protect include sulphonamido, amido, amino and aldehyde. Suitable protecting groups for sulphonamido, amido and amino include tert-butyloxycarbonyl, benzyloxycarbonyl, 2-trimethylsilylethoxycarbonyl (Teoc) or tert-butyl. Suitable protecting groups for aldehyde include alcohols, such as methanol or ethanol, and diols, such as 1,3-propanediol or, preferably, 1,2-ethanediol (so forming a cyclic acetal).

The protection and deprotection of functional groups may take place before or after a reaction in the above-mentioned schemes.

Protecting groups may be removed in accordance with techniques that are well known to those skilled in the art and as described hereinafter. For example, protected compounds/intermediates described herein may be converted chemically to unprotected compounds using standard deprotection techniques (e.g. using a protic acid or a Lewis acid such as trifluoroacetic acid, sulfuric acid, toluenesulfonic acid, boron trichloride or Sc(OTf)₃).

Persons skilled in the art will appreciate that, in order to obtain compounds of the invention in an alternative, and, on some occasions, more convenient, manner, the individual process steps mentioned hereinbefore may be performed in a different order, and/or the individual reactions may be performed at a different stage in the overall route (i.e. substituents may be added to and/or chemical transformations performed upon, different intermediates to those mentioned hereinbefore in conjunction with a particular reaction). This may negate, or render necessary, the need for protecting groups.

The type of chemistry involved will dictate the need, and type, of protecting groups as well as the sequence for accomplishing the synthesis.

The use of protecting groups is fully described in “Protective Groups in Organic Chemistry”, edited by J W F McOmie, Plenum Press (1973), and “Protective Groups in Organic Synthesis”, 3^(rd) edition, T. W. Greene & P. G. M. Wutz, Wiley-Interscience (1999).

Medical and Pharmaceutical Uses

Compounds of the invention are useful because they possess pharmacological activity. The compounds of the invention are therefore indicated as pharmaceuticals.

According to a further aspect of the invention there is thus provided the compounds of the invention for use as pharmaceuticals.

In particular, compounds of the invention are agonists of AngII, more particularly, are agonists of the AT2 receptor, and, especially, are selective agonists of that sub-receptor, for example as may be demonstrated in the tests described below.

The compounds of the invention are thus expected to be useful in those conditions in which endogenous production of AngII is deficient and/or where an increase in the effect of AngII is desired or required.

The compounds of the invention are further expected to be useful in those conditions where AT2 receptors are expressed and their stimulation is desired or required.

The compounds of the invention are further indicated in the treatment of conditions characterised by vasoconstriction, increased cell growth and/or differentiation, increased cardiac contractility, increased cardiovascular hypertrophy, and/or increased fluid and electrolyte retention.

The compounds of the invention are further indicated in the treatment of stress-related disorders, and/or in the improvement of microcirculation and/or mucosa-protective mechanisms.

Thus, compounds of the invention are expected to be useful in the treatment of disorders, which may be characterised as indicated above, and which are of, for example, the gastrointestinal tract, the cardiovascular system, the respiratory tract, the kidneys, the eyes, the female reproductive (ovulation) system and the central nervous system (CNS).

Disorders of the gastrointestinal tract that may be mentioned include oesophagitis, Barrett's oesophagus, gastric ulcers, duodenal ulcers, dyspepsia (including non-ulcer dyspepsia), gastro-oesophageal reflux, irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), pancreatitis, hepatic disorders (such as hepatitis), gall bladder disease, multiple organ failure (MOF) and sepsis. Other gastrointestinal disorders that may be mentioned include xerostomia, gastritis, gastroparesis, hyperacidity, disorders of the bilary tract, coelicia, Crohn's disease, ulcerative colitis, diarrhoea, constipation, colic, dysphagia, vomiting, nausea, indigestion and Sjögren's syndrome.

Disorders of the respiratory tract that may be mentioned include inflammatory disorders, such as asthma, obstructive lung diseases (such as chronic obstructive lung disease), pneumonitis, pulmonary hypertension and adult respiratory distress syndrome.

Disorders of the kidneys that may be mentioned include renal failure, nephritis and renal hypertension.

Disorders of the eyes that may be mentioned include diabetic retinopathy, premature retinopathy and retinal microvascularisation.

Disorders of the female reproductive system that may be mentioned include ovulatory dysfunction.

Cardiovascular disorders that may be mentioned include hypertension, cardiac hypertrophy, cardiac failure, artherosclerosis, arterial thrombosis, venous thrombosis, endothelial dysfunction, endothelial lesions, post-balloon dilatation stenosis, angiogenesis, diabetic complications, microvascular dysfunction, angina, cardiac arrhythmias, claudicatio intermittens, preeclampsia, myocardial infarction, reinfarction, ischaemic lesions, erectile dysfunction and neointima proliferation.

Disorders of the CNS that may be mentioned include cognitive dysfunctions, dysfunctions of food intake (hunger/satiety) and thirst, stroke, cerebral bleeding, cerebral embolus and cerebral infarction.

Compounds of the invention may also be useful in the modulation of growth metabolism and proliferation, for example in the treatment of hypertrophic disorders, prostate hyperplasia, autoimmune disorders, psoriasis, obesity, neuronal regeneration, the healing of ulcers, inhibition of adipose tissue hyperplasia, stem cell differentiation and proliferation, cancer (e.g. in the gastrointestinal tract, lung cancer, etc), apoptosis, tumours (generally) and hypertrophy, diabetes, neuronal lesions and organ rejection.

The compounds of the invention are indicated both in the therapeutic and/or prophylactic treatment of the above conditions.

According to a further aspect of the present invention, there is provided a method of treatment of a condition in which endogenous production of AngII is deficient, and/or a condition where an increase in the effect of AngII is desired or required, and/or a condition where AT2 receptors are expressed and their stimulation is desired or required, which method comprises administration of a therapeutically effective amount of a compound of the invention to a person suffering from, or susceptible to, such a condition.

The compounds of the invention will normally be administered orally, intravenously, subcutaneously, buccally, rectally, dermally, nasally, tracheally, bronchially, by any other parenteral route or via inhalation, in a pharmaceutically acceptable dosage form.

When the condition to be treated is multiple organ failure, preferred routes of administration are parenteral (e.g. by injection). Otherwise, the preferred route of administration for compounds of the invention is oral.

The compounds of the invention may be administered alone, but are preferably administered by way of known pharmaceutical formulations, including tablets, capsules or elixirs for oral administration, suppositories for rectal administration, sterile solutions or suspensions for parenteral or intramuscular administration, and the like.

Such formulations may be prepared in accordance with standard and/or accepted pharmaceutical practice.

According to a further aspect of the invention there is thus provided a pharmaceutical formulation including a compound of the invention, in admixture with a pharmaceutically acceptable adjuvant, diluent or carrier.

Compounds of the invention may also be administered in combination with other AT2 agonists that are known in the art, as well as in combination with AT1 receptor antagonists that are known in the art, such as losartan, or in combination with an inhibitor of angiotensin converting enzyme (ACE).

According to a further aspect of the invention, there is provided a combination product comprising:

(A) a compound of the invention; and

(B) an AT1 receptor antagonist, or an ACE inhibitor,

wherein each of components (A) and (B) is formulated in admixture with a pharmaceutically-acceptable adjuvant, diluent or carrier.

Such combination products provide for the administration of compound of the invention in conjunction with an AT1 receptor antagonist, or an ACE inhibitor, and may thus be presented either as separate formulations, wherein at least one of those formulations comprises compound of the invention, and at least one comprises AT1 receptor antagonist, or ACE inhibitor, or may be presented (i.e. formulated) as a combined preparation (i.e. presented as a single formulation including compound of the invention and AT1 receptor antagonist or ACE inhibitor).

Thus, there is further provided:

(1) a pharmaceutical formulation including a compound of the invention and an AT1 receptor antagonist, or an ACE inhibitor, in admixture with a pharmaceutically-acceptable adjuvant, diluent or carrier; and

(2) a kit of parts comprising components:

-   (a) a pharmaceutical formulation including a compound of the     invention, in admixture with a pharmaceutically-acceptable adjuvant,     diluent or carrier; and -   (b) a pharmaceutical formulation including an AT1 receptor     antagonist, or an ACE inhibitor, in admixture with a     pharmaceutically-acceptable adjuvant, diluent or carrier,     which components (a) and (b) are each provided in a form that is     suitable for administration in conjunction with the other.

Depending upon the disorder and patient to be treated and the route of administration, the compounds of the invention may be administered at varying doses.

Although doses will vary from patient to patient, suitable daily doses are in the range of about 1 to 1000 mg per patient, administered in single or multiple doses. More preferred daily doses are in the range 2.5 to 250 mg per patient.

Individual doses of compounds of the invention may be in the range 1 to 100 mg.

In any event, the physician, or the skilled person, will be able to determine the actual dosage which will be most suitable for an individual patient, which is likely to vary with the condition that is to be treated, as well as the age, weight, sex and response of the particular patient to be treated. The above-mentioned dosages are exemplary of the average case; there can, of course, be individual instances where higher or lower dosage ranges are merited, and such are within the scope of this invention.

Compounds of the invention have the advantage that they bind selectively to, and exhibit agonist activity at, the AT2 receptor. By compounds which “bind selectively” to the AT2 receptor, we include that the affinity ratio for the relevant compound (AT2:AT1) is at least 5:1, preferably at least 10:1 and more preferably at least 20:1.

The compounds of the invention may also have the advantage that they may be more efficacious than, be less toxic than, be longer acting than, be more potent than, produce fewer side effects than, be more easily absorbed than, and/or have a better pharmacokinetic profile (e.g. higher oral bioavailability and/or lower clearance) than, and/or have other useful pharmacological, physical, or chemical properties over, compounds known in the prior art.

Biological Tests

The following test procedures may be employed.

Test A

Receptor Binding Assay Using Rat Liver Membrane AT₁ Receptor

Rat liver membranes were prepared according to the method of Dudley et al (Mol. Pharmacol. (1990) 38, 370). Binding of [¹²⁵I]Ang II to membranes was conducted in a final volume of 0.5 mL containing 50 mM Tris-HCl (pH 7.4), 100 mM NaCl, 10 mM MgCl₂, 1 mM EDTA, 0.025% bacitracin, 0.2% BSA (bovine serum albumin), liver homogenate corresponding to 5 mg of the original tissue weight, [¹²⁵I]Ang II (70 000 cpm, 0.03 nM) and variable concentrations of test substance. Samples were incubated at 25° C. for 1 h, and binding was terminated by filtration through Whatman GF/B glass-fiber filter sheets using a Brandel cell harvester. The filters were washed with 4×2 mL of Tris-HCl (pH 7.4) and transferred to tubes. The radioactivity was measured in a gamma counter. The characteristics of the Ang II binding AT₁ receptor were determined by using six different concentrations (0.03-5 nmol/L) of the labeled [¹²⁵I]AngII. Non-specific binding was determined in the presence of 1 μM Ang II. The specific binding was determined by subtracting the non-specific binding from the total bound [¹²⁵I]AngII. The dissociation constant (K_(d)=1.7±0.1 nM, [L]=0.057 nM) was determined by Scatchard analysis of data obtained with Ang II by using GraFit (Erithacus Software, UK). The binding data were best fitted with a one-site fit. All experiments were performed at least in triplicate.

Test B

Receptor Binding Assay Using Porcine Myometrial Membrane AT₂ Receptor

Myometrial membranes were prepared from porcine uteri according to the method by Nielsen et al (Clin. Exp. Pharm. Phys. (1997) 24, 309). Any possible interference that may be exhibited by binding of compound to AT₁ receptors was blocked by addition of 1 μM of a selective AT1 inhibitor. Binding of [¹²⁵I]Ang II to membranes was conducted in a final volume of 0.5 mL containing 50 mM Tris-HCl (pH 7.4), 100 mM NaCl, 10 mM MgCl₂, 1 mM EDTA, 0.025% bacitracin, 0.2% BSA, homogenate corresponding to 10 mg of the original tissue weight, [¹²⁵I]Ang II (70 000 cpm, 0.03 nM) and variable concentrations of test substance. Samples were incubated at 25° C. for 1 h, and binding was terminated by filtration through Whatman GF/B glass-fiber filter sheets using a Brandel cell harvester. The filters were washed with 3×3 mL of Tris-HCl (pH 7.4) and transferred to tubes. The radioactivity was measured using a gamma counter. The characteristics of the Ang II binding AT₂ receptor was determined by using six different concentrations (0.03-5 nmol/L) of the labeled [¹²⁵I]Ang II. Non-specific binding was determined in the presence of 1 μM Ang II. The specific binding was determined by subtracting the non-specific binding from the total bound [¹²⁵I]Ang II. The dissociation constant (K_(d)=0.7±0.1 nM, [L]=0.057 nM) was determined by Scatchard analysis of data obtained with Ang II by using GraFit (Erithacus Software, UK). The binding data were best fitted with a one-site fit. All experiments were performed at least in triplicate.

Test C

Duodenal Mucosal Alkaline Secretion Assay

Compounds were exposed to the duodenal mucosa in barbiturate-anaesthetised rats prepared for in situ titration of duodenal mucosal alkaline secretion, according to the methodology described by Flemström et al in Am. J. Physiol. (1982) 243, G348.

The invention is illustrated by way of the following examples.

EXAMPLE 1 N-Butyloxycarbonyl-3-(3-pyrrolidine-2,5-dione-1-ylmethylphenyl)-5-iso-butylthiophene-2-sulfonamide (a) N-tert-Butylthiophene-2-sulfonamide

Thiophene-2-sulfonyl chloride (15 g, 0.082 mol) was dissolved in CHCl₃ (200 mL) under N₂ atmosphere and then cooled to 0° C. tert-Butylamine (25.9 mL, 0.246 mol) dissolved in CHCl₃ (50 mL) was then added dropwise to the reaction mixture. The reaction mixture was stirred for 1 h at room temperature and then at reflux for 10 min. Toluene (700 mL) was added and the organic phase was washed with water (3×50 mL), dried, and concentrated in vacuo. The sub-title product was used without further purification in the next step.

¹H NMR δ (CDCl₃): 7.60 (1H, dd, J=1.3, 3.8 Hz), 7.53 (1H, dd, J=1.3, 5.0 Hz), 7.02 (1H, dd, J=5.0, 3.8 Hz), 5.13 (1H, m), 1.24 (9H, m).

¹³C NMR δ (CDCl₃): 145.0, 131.7, 131.2, 127.0, 55.1, 29.9.

(b) 5-iso-Butyl-N-tert-butylthiophene-2-sulfonamide

N-tert-Butylthiophene-2-sulfonamide (10 g, 0.046 mol, see step (a) above) was dissolved in THF (85 mL) under N₂ and then cooled to −78° C. n-BuLi (1.6 M, 76.9 mL, 0.12 mol) was added via a syringe. The reaction mixture was stirred at −78° C. for 30 min. and then at −40° C. for 2 h. Iodo-2-methylpropane (10.5 mL, 0.09 mol) was added dropwise to the reaction mixture. The reaction mixture was stirred overnight at room temperature. The reaction was quenched with NH₄Cl (aq.) and extracted with EtOAc. The combined organic phase was washed with brine and dried and concentrated in vacuo. The crude product was purified on column chromatography (hexanes:EtOAc (10:1)) to give the sub-title compound in 55% yield (7.0 g, 0.025 mol).

¹H NMR δ (CDCl₃): 7.43 (1H, d, J=3.6 Hz), 6.67 (1H, d, J=3.8 Hz), 4.83 (1H, m), 2.67 (2H, d, J=7 Hz), 1.88 (1H, m), 1.26 (9H, m), 0.93 (6H, J=6.6 Hz).

¹³C NMR δ (CDCl₃): 145.0, 131.7, 131.2, 127.0, 55.1, 29.9.

(c) 5-iso-Butyl-2-(N-tert-butylaminosulfonyl)thiophene-3-boronic acid

5-iso-Butyl-N-tert-butylthiophene-2-sulfonamide (10.6 g, 0.039 mol, see step (b) above) was dissolved in THF (165 mL) under N₂ and then cooled to −78° C. n-BuLi (1.6 M, 60.19 mL, 0.096 mol) was added via a syringe. The reaction mixture was stirred at −20° C. for 4 h. The tri-iso-propylborate (13.3 mL, 0.058 mol) was then added via a syringe and the reaction mixture was stirred overnight at room temperature. The reaction was quenched with 2 M HCl (20 mL). The organic phase was separated and the water phase was extracted with EtOAc (3×100 mL). The combined organic phase was washed with brine, dried and concentrated in vacuo. The product was used without further purification. MS (ESI⁺) m/z: 236.8

(d) 3-(3-Hydroxymethylphenyl)-5-iso-butyl-N-tert-butylthiophene-2-sulfonamide

A mixture of m-bromobenzyl alcohol (1.05 g, 5.80 mmol), 5-iso-butyl-2-(N-tert-butylaminosulfonyl)thiophene-3-boronic acid (2.41 g, 7.55 mmol; see step (c)), Pd(PPh₃)₄ (270 mg, 0.235 mmol), NaOH (19.1 mL, 1.5 M aq, 28.6 mmol), EtOH (5.0 mL) and toluene (30 mL) was stirred under N₂ at 90° C. for about 4 h. After cooling, water (10 mL) was added to the reaction mixture and this was then extracted with ethyl acetate. The combined organic phase was dried and concentrated in vacuo. The crude product was purified on column chromatography (EtOAc/hexane, 30:70) to give sub-title compound as a colourless syrup in 57% yield (1.26 g, 3.31 mmol).

¹H NMR δ (CDCl₃): 0.96 (d, J=6.6 Hz, 6H), 0.98 (s, 9H), 1.82-2.00 (m, 1H), 2.66 (d, J=7.1 Hz, 2H), 3.28 (br s, 1H), 4.67 (s, 2H), 4.81 (br s, 1H), 6.76 (s, 1H), 7.30-7.50 (m, 3H), 7.64 (s, 1H).

¹³C NMR δ (CDCl₃): 22.1, 29.4, 30.4, 39.1, 54.4, 64.6, 127.1, 127.8, 128.5, 129.0, 134.9, 136.2, 141.2, 143.2, 148.2.

MS (ESI) m/z: 382 (M+1)⁺.

IR ν (neat, cm⁻¹): 3498, 3286, 2958, 2870, 1465, 1313.

Anal. Calcd. for C₁₉H₂₇NO₃S₂: C, 59.81; H, 7.13; N, 3.67. Found: C, 60.05; H, 7.31; N, 3.90.

(e) 3-(3-Bromomethylphenyl)-5-iso-butyl-N-tert-butylthiophene-2-sulfonamide

A mixture of 3-(3-hydroxymethylphenyl)-5-iso-butyl-N-tert-butylthiophene-2-sulfonamide (246 mg, 0.644 mmol; see step (d)), CBr₄ (534 mg, 1.61 mmol) and PPh₃ (422 mg, 1.61 mmol) in DMF (5.0 mL) was stirred at room temperature overnight. Water (10 mL) was then added and the reaction mixture was extracted with ethyl acetate. The combined organic phase was washed with water, dried and concentrated in vacuo. The crude product was purified on column chromatography (Hex/EtOAc 9:1) to give the sub-title compound as a white solid in 95% yield (273 mg, 0.612 mmol).

¹H NMR δ (CDCl₃): 0.97 (d, J=6.3 Hz, 6H), 0.98 (s, 12H), 1.84-2.00 (m, 1H), 2.69 (d, J=7.1 Hz, 2H), 4.18 (br s, 1H), 4.54 (s, 2H), 6.78 (s, 1H), 7.37-7.44 (2H, m), 7.50-7.56 (m, 1H), 7.69 (br s, 1H).

¹³C NMR δ (CDCl₃): 22.2, 29.5, 30.5, 33.3, 39.2, 54.4, 128.6, 128.8, 128.97, 129.02, 129.7, 135.5, 136.8, 138.3, 142.1, 148.5.

MS (ESI) m/z: 444 (M+H)⁺, 446 ((M+H)⁺+2).

IR ν (neat, cm⁻¹): 3296, 2969, 2870, 1586, 1452, 1303.

Anal. Calcd. for C₁₉H₂₆BrNO₂S₂: C, 51.34; H, 5.90; N, 3.15. Found: C, 51.44; H, 6.02; N, 3.22.

(f) 3-(3-Pyrrolidine-2,5-dione-1-ylmethylphenyl)-5-iso-butyl-N-tert-butylthiophene-2-sulfonamide

To a solution of succinimide (66.6 mg, 0.672 mmol) in DMSO (1 mL) and t-BuOK (52.8 mg, 0.470 mmol), that had been stirred for 40 min at ambient temperature, was added a solution of 3-(3-bromomethylphenyl)-5-iso-butyl-N-tert-butylthiophene-2-sulfonamide (99.5 mg, 0.224 mmol; see step (e)) in DMSO (1 mL) dropwise. The reaction mixture was stirred for 1 h at ambient temperature and then diluted with CH₂Cl₂ (15 mL). The organic layer was washed with water, dried (over anhydrous MgSO₄), concentrated in vacuo, and the residue purified by flash chromatography using MeOH:CH₂Cl₂ (3:97) as eluent to give the sub-title compound in 94% yield as a colourless syrup (97.1 mg, 0.210 mmol).

¹H NMR δ (CDCl₃): 0.90 (s, 9H), 0.95 (d, J=6.6 Hz, 6H), 1.80-2.00 (m, 1H), 2.65 (d, J=7.1 Hz, 2H), 2.83 (s, 4H), 4.59 (s, 1H), 4.75 (s, 2H), 6.79 (s, 1H), 7.26-7.44 (m, 3H), 7.58 (m, 1H).

¹³C NMR δ (CDCl₃): 22.1, 28.4, 29.2, 30.4, 39.1, 41.7, 54.0, 126.6, 127.1, 127.2, 128.2, 128.7, 135.0, 135.5, 136.7, 142.1, 148.3, 178.1.

IR ν (neat, cm⁻¹): 3306, 3058, 2960, 1708, 1702, 1428, 1400, 1321.

MS (ESI) m/z: 463 (M+H)⁺.

Anal. Calcd. for C₂₃H₃₀N₂O₄S₂: C, 59.71; H, 6.54; N, 6.06. Found: C, 59.91; H, 6.74; N, 5.94.

(g) N-Butyloxycarbonyl-3-(3-pyrrolidine-2,5-dione-1-ylmethylphenyl)-5-iso-butylthiophene-2-sulfonamide

To a solution of 3-(3-pyrrolidine-2,5-dione-1-ylmethylphenyl)-5-iso-butyl-N-tert-butylthiophene-2-sulfonamide (95.0 mg, 0.205 mmol; see step (f)) in CH₂Cl₂ (2 mL) was added BCl₃ (0.6 mL, 1.0 M in hexane) and the reaction mixture was stirred for 1 h at ambient temperature. The reaction mixture was concentrated in vacuo. Water (5 mL) was added to the residue and this was then extracted with EtOAc. The combined organic phase was washed with water and brine, dried (over anhydrous MgSO₄) and concentrated in vacuo. To the crude product dissolved in pyridine (1.5 mL) was added pyrrolidinopyridine (91.3 mg, 0.616 mmol) and butyl chloroformate (261.1 μL, 2.05 mmol) and the reaction mixture was stirred overnight. Citric acid (3 mL, 10% aq) was added to the reaction mixture, which was then extracted with EtOAc, dried (over anhydrous MgSO₄), concentrated in vacuo, and the residue was purified by LCMS (Liquid Chromatography Mass Spectrum; 25-100% CH₃CN in water) to give the title compound in 76% yield, over two steps, (79.1 mg, 0.156 mmol).

¹H NMR δ (CDCl₃): 0.88 (t, J=7.3 Hz, 3H), 0.99 (d, J=6.6 Hz, 6H), 1.16-1.34 (m, 2H), 1.46-1.58 (m, 2H), 1.86-2.04 (m, 1H), 2.71 (d, J=7.1 Hz, 2H), 2.77 (s, 4H), 4.04 (t, J=6.7 Hz, 2H), 4.73 (s, 2H), 6.83 (s, 1H), 7.24-7.42 (m, 3H), 7.67 (s, 1H), 8.74 (s, 1H).

¹³C NMR δ (CDCl₃): 13.6, 18.7, 22.2, 28.4, 30.4, 30.5, 39.3, 42.3, 66.6, 127.8, 128.5, 128.6, 128.9, 129.0, 131.1, 134.1, 135.2, 144.9, 150.4, 151.6, 178.2.

IR ν (neat, cm⁻¹): 3202, 2960, 2934, 2872, 1749, 1701, 1433, 1402, 1345, 1159.

MS (ESI) m/z: 507 (M+H)⁺.

Anal. Calcd. for C₂₄H₃₀N₂O₆S₂: C, 56.90; H, 5.97; N, 5.53. Found: C, 56.76; H, 5.89; N, 5.51.

EXAMPLE 2 N-Butyloxycarbonyl-3-(3-pyrrolidine-2-one-1-ylmethylphenyl)-5-iso-butylthiophene-2-sulfonamide (a) 3-(3-Pyrrolidine-2-one-1-ylmethylphenyl)-5-iso-butyl-N-tert-butylthiophene-2-sulfonamide

To a solution of 2-pyrrolidinone (26.5 mg, 0.312 mmol) in DMSO (1 mL) and t-BuOK (48.9 mg, 0.436 mmol), that had been stirred for 40 min at ambient temperature, was added a solution of 3-(3-bromomethylphenyl)-5-iso-butyl-N-tert-butylthiophene-2-sulfonamide (92.3 mg, 0.208 mmol; see Example 1(e)) in DMSO (1 mL) dropwise. The reaction mixture was stirred for 1 h at ambient temperature and then diluted with CH₂Cl₂ (15 mL). The organic layer was washed with water, dried (over anhydrous MgSO₄), concentrated in vacuo, and the residue purified by flash chromatography using MeOH:CH₂Cl₂ (2:98) as eluent to give the sub-title compound in 77% yield as a colourless syrup (72.3 mg, 0.161 mmol).

¹H NMR δ (CDCl₃): 0.95 (d, J=6.6 Hz, 6H), 0.96 (s, 9H), 1.82-1.98 (m, 1H), 2.00-2.14 (m, 2H), 2.51 (t, J=8.1 Hz, 2H), 2.66 (d, J=7.1 Hz, 2H), 3.44 (t, J=7.1 Hz, 2H), 4.49 (s, 2H), 4.96 (s, 1H), 6.80 (s, 1H), 7.19-7.27 (m, 1H), 7.34-7.42 (m, 2H), 7.60 (s, 1H).

¹³C NMR δ (CDCl₃): 17.9, 22.1, 29.4, 30.5, 30.8, 39.1, 46.5, 47.9, 54.1, 127.1, 127.40, 127.45, 128.4, 128.6, 135.0, 136.7, 136.9, 142.1, 148.0, 176.2.

IR ν (neat, cm⁻¹): 3206, 3058, 2960, 2871, 1671, 1465, 1434, 1313.

MS (ESI) m/z: 449 (M+H)⁺.

Anal. Calcd. for C₂₃H₃₂N₂O₃S₂: C, 61.57; H, 7.19; N, 6.24. Found: C, 61.56; H, 7.31; N, 6.20.

(b) N-Butyloxycarbonyl-3-(3-pyrrolidine-2-one-1-ylmethylphenyl)-5-iso-butyl-thiophene-2-sulfonamide

To a solution of 3-(3-pyrrolidine-2-one-1-ylmethylphenyl)-5-iso-butyl-N-tert-butylthiophene-2-sulfonamide (66.7 mg, 0.149 mmol; see step (a)) in CH₂Cl₂ (2 mL) was added BCl₃ (0.6 mL, 1.0 M in hexane) and the reaction mixture was stirred for 1 h at ambient temperature. The reaction mixture was concentrated in vacuo. Water (5 mL) was added to the residue and this was then extracted with EtOAc. The combined organic phase was washed with water and brine, dried (over anhydrous MgSO₄) and concentrated in vacuo. To the crude product dissolved in pyridine (1.5 mL) was added pyrrolidinopyridine (44.1 mg, 0.297 mmol) and butyl chloroformate (189.1 μL, 1.49 mmol) and the reaction mixture was stirred overnight. Citric acid (3 mL, 10% aq) was added to the reaction mixture, which was then extracted with EtOAc, dried (over anhydrous MgSO₄), concentrated in vacuo, and the residue purified by LCMS (20-100% CH₃CN in water) to give the title compound in 74% yield, over two steps, (54 mg, 0.110 mmol).

¹H NMR δ (CDCl₃): 0.88 (t, J=7.2 Hz, 3H), 0.98 (d, J=6.6 Hz, 6H), 1.20-1.40 (m, 2H), 1.50-1-65 (m, 2H), 1.85-2.10 (m, 3H), 2.47 (t, J=8.0 Hz, 2H), 2.70 (d, J=7.1 Hz, 2H), 3.44 (t, J=7.1 Hz, 2H), 4.08 (t, J=6.8 Hz, 2H), 4.44 (s, 2H), 6.86 (s, 1H), 7.15-7.23 (m, 1H), 7.29-7.40 (m, 2H), 7.80 (s, 1H), 10.04 (br s, 1H).

¹³C NMR δ (CDCl₃): 13.6, 17.8, 18.8, 22.2, 30.4, 30.5, 31.2, 39.3, 47.2, 47.9, 66.4, 127.6, 127.8, 128.2, 128.3, 129.7, 131.4, 134.3, 136.3, 144.6, 151.0, 151.3, 177.2.

IR ν (neat, cm⁻¹): 3051, 2959, 2871, 1747, 1662, 1466, 1347.

MS (ESI) m/z: 493 (M+H)⁺.

Anal. Calcd. for C₂₄H₃₂N₂O₅S₂: C, 58.51; H, 6.55; N, 5.69. Found: C, 58.35; H, 6.63; N, 5.75.

EXAMPLE 3 N-Butyloxycarbonyl-3-[3-(3-methylimidazolidine-2,5-dione-1-ylmethyl)phenyl]-5-iso-butylthiophene-2-sulfonamide (a) 3-[3-(3-Methylimidazolidine-2,5-dione-1-ylmethyl)phenyl]-5-iso-butyl-N-tert-butylthiophene-2-sulfonamide

To a solution of 1-methylhydantoin (33.9 mg, 0.297 mmol) in DMSO (1 mL) and t-BuOK (46.6 mg, 0.415 mmol), that had been stirred for 40 min at ambient temperature, was added a solution of 3-(3-bromomethylphenyl)-5-iso-butyl-N-tert-butylthiophene-2-sulfonamide (87.9 mg, 0.198 mmol; see Example 1(e)) in DMSO (1 mL) dropwise. The reaction mixture was stirred for 1 h at ambient temperature and then diluted with CH₂Cl₂ (15 mL). The organic layer was washed with water, dried (over anhydrous MgSO₄), concentrated in vacuo, and the residue purified by flash chromatography using EtOAc:petroleum ether (35:65) as eluent to give the sub-title compound in 54% yield as a colourless syrup (51.5 mg, 0.107 mmol).

¹H NMR δ (CDCl₃): 0.90 (s, 9H), 0.95 (d, J=6.6 Hz, 6H), 1.82-1.98 (m, 1H), 2.66 (d, J=6.8 Hz, 2H), 3.03 (s, 3H), 4.02 (s, 2H), 4.77 (s, 2H), 4.99 (s, 1H), 6.81 (s, 1H), 7.26-7.44 (m, 3H), 7.69 (m, 1H).

¹³C NMR δ (CDCl₃): 22.1, 29.3, 29.8, 30.5, 39.2, 41.9, 52.0, 53.9, 126.7, 126.9, 127.2, 128.2, 128.7, 135.0, 135.9, 136.9, 142.1, 148.2, 157.0, 170.5.

MS (ESI) m/z: 478 (M+H)⁺.

IR ν (neat, cm⁻¹): 3276, 3057, 2960, 2870, 1771, 1716, 1488, 1451, 1317.

Anal. Calcd. for C₂₃H₃₁N₃O₄S₂: C, 57.84; H, 6.54; N, 8.80. Found: C, 58.02; H, 6.77; N, 8.93.

(b) N-Butyloxycarbonyl-3-[3-(3-methylimidazolidine-2,5-dione-1-ylmethyl)-phenyl]-5-iso-butylthiophene-2-sulfonamide

To a solution of 3-[3-(3-methylimidazolidine-2,5-dione-1-ylmethyl)phenyl]-5-iso-butyl-N-tert-butylthiophene-2-sulfonamide (42.1 mg, 0.088 mmol; see step (a)) in CH₂Cl₂ (2 mL) was added BCl₃ (0.6 mL, 1.0 M in hexane) and the reaction mixture was stirred for 1 h at ambient temperature. The reaction mixture was concentrated in vacuo. Water (5 mL) was added to the residue and this was then extracted with EtOAc. The combined organic phase was washed with water, and brine, dried (over anhydrous MgSO₄) and concentrated in vacuo. To the crude product dissolved in pyridine (1.5 mL) was added pyrrolidinopyridine (26.1 mg, 0.176 mmol) and butyl chloroformate (112.0 μL, 0.88 mmol) and the reaction mixture was stirred overnight. Citric acid (3 mL, 10% aq) was added to the reaction mixture, which was then extracted with EtOAc, dried (over anhydrous MgSO₄), concentrated in vacuo, and the residue purified by flash chromatography using MeOH:CH₂Cl₂ (3:97) as eluent and then with LCMS (30-100% CH₃CN in water) to give the title compound in 80% yield, over two steps, (36.6 mg, 0.702 mmol).

¹H NMR δ (CDCl₃): 0.86 (t, J=7.2 Hz, 3H), 0.98 (d, J=6.7 Hz, 6H), 1.15-1.30 (m, 2H), 1.42-1.58 (m, 2H), 1.88-2.04 (m, 1H), 2.70 (d, J=6.9 Hz, 2H), 3.00 (s, 3H), 3.94 (s, 2H), 4.00 (t, J=6.6 Hz, 2H), 4.73 (s, 2H), 6.85 (s, 1H), 7.22-7.32 (m, 1H), 7.32-7.44 (m, 2H), 7.75 (s, 1H), 9.26 (br s, 1H).

¹³C NMR δ (CDCl₃): 13.6, 18.7, 22.2, 29.7, 30.41, 30.45, 39.3, 42.4, 51.9, 66.4, 127.7, 128.4, 128.85, 128.93, 131.3, 134.0, 135.6, 144.6, 150.5, 151.3, 157.1, 170.2.

IR ν (neat, cm⁻¹): 3124, 2959, 2933, 2872, 1750, 1702, 1488, 1452, 1345.

MS (ESI) m/z: 522 (M+H)⁺.

Anal. Calcd. for C₂₄H₃₁N₃O₆S₂×1½H₂O: C, 52.54; H, 6.25; N, 7.66. Found: C, 52.25; H, 6.05; N, 7.91.

EXAMPLE 4

Title compounds of the Examples were tested in Tests A and B above and were found to exhibit an affinity for AT2 receptors of less than Ki=100 nM (e.g. less than 50 nM). The title compounds of the Examples were found to exhibit an affinity to AT1 receptors of more than Ki=500 nM (e.g. more than 1 μM).

EXAMPLE 5

Title compounds of the Examples are tested in Test C above and are found to stimulate markedly mucosal alkalisation. This effect is blocked by co-administration of the selective AT2 receptor antagonist PD123319 (Sigma Chemical Company). 

1. A compound of formula I,

wherein X₁ represents —C(R^(1a))(R^(1b))—, —N(R^(1a))— or —O—; the dotted line signifies an optional double bond; and in the case when the dotted line does not signify a double bond, X₂ and X₃ independently represent —C(R^(1c))(R^(1d))—, —N(R^(1e))—, —O—, —C(O)— or —C(R^(1f))(R^(1g))—C(R^(1h))(R^(1j))— provided that: (i) when X₁ represents —N(R^(1a))—, then X₂ and X₃ do not both represent —N(R^(1e))—; (ii) when X₁ represents —O—, then X₂ and X₃ do not both represent —O—; (iii) when X₁ represents —O— and X₂ represents —N(R^(1e))—, then X₃ represents —C(O)—; and (iv) when X₁ represents —O— and X₃ represents —N(R^(1e))—, then X₂ does not represent —C(R^(1c))(R^(1d))—; or in the case when the dotted lines signifies a double bond, X² and X³ independently represent —N— or —C(R^(1c))—; R^(1a), R^(1b), R^(1c), R^(1d), R^(1e), R^(1f), R^(1g), R^(1h) and R^(1j) independently represent H, C₁₋₆ alkyl, C₁₋₆ alkoxy, C₁₋₆ alkoxy-C₁₋₆ alkyl, Ar¹, Het¹, C₁₋₃ alkyl-Ar², C₁₋₃ alkyl-Het², C₁₋₃ alkoxy-Ar³, C₁₋₃ alkoxy-Het³, halo, —C(O)—C₁₋₆ alkyl, —C(O)—Ar⁴ or —C(O)—Het⁴; Ar¹, Ar², Ar³ and Ar⁴ each independently represent a C₆₋₁₀ aryl group, which group is optionally substituted by one or more substituents selected from ═O, —OH, cyano, halo, nitro, C₁₋₆ alkyl (optionally terminated by —N(H)C(O)OR^(11a)), C₁₋₆ alkoxy, phenyl, —N(R^(12a))R^(12b), —C(O)R^(12c), —C(O)OR^(12d), —C(O)N(R^(12e))R^(12f), —N(R^(12g))C(O)R^(12h), —N(R^(12i))C(O)N(R^(12k), —N(R^(12m))S(O)₂R^(11b), —S(O)_(p)R^(11C), —OS(O)₂R^(11d) and —S(O)₂N(R^(12n))R^(12p); Het¹, Het², Het³ and Het⁴ each independently represent a four- to twelve-membered heterocyclic group containing one or more heteroatoms selected from oxygen, nitrogen and/or sulfur, which heterocyclic group is optionally substituted by one or more substituents selected from ═O, —OH, cyano, halo, nitro, C₁₋₆ alkyl (optionally terminated by —N(H)C(O)OR^(11a)), C₁₋₆ alkoxy, phenyl, —N(R^(12a))R^(12b), —C(O)R^(12c), —C(O)OR^(12d), —C(O)N(R^(12e))R^(12f), —N(R^(12g))C(O)R^(12h), —N(R^(12i))C(O)N(R^(12j))R^(12k), —N(R^(12m))S(O)₂R^(11b), —S(O)_(p)R^(11c), —OS(O)₂R^(11d) and —S(O)₂N(R^(12n))R^(12p); R^(11a) to R^(11d) independently represent C₁₋₆ alkyl; R^(12a) to R^(12p) independently represent H or C₁₋₆ alkyl; p represents 0, 1 or 2; A represents —C(O) or —CH₂—; Y₁, Y₂, Y₃ and Y₄ independently represent —CH— or —CF—; Z₁ represents —S—; Z₂ represents —CH—; R² represents —S(O)₂N(H)C(O)R⁴, —S(O)₂N(H)S(O)₂R⁴, —C(O)N(H)S(O)₂R⁴, or, when Z₁ represents —CH═CH—, R² may represent —N(H)S(O)₂N(H)C(O)R⁵ or —N(H)C(O)N(H)S(O)₂R⁵; R³ represents C₁₋₆ alkyl, C₁₋₆ alkoxy, C₁₋₆ alkoxy-C₁₋₆-alkyl or di-C₁₋₃-alkylamino-C₁₋₄-alkyl; R⁴ represents C₁₋₆ alkyl, C₁₋₆ alkoxy, C₁₋₆ alkoxy-C₁₋₆-alkyl, C₁₋₃ alkoxy-C₁₋₆-alkoxy, C₁₋₆ alkylamino or di-C₁₋₆ alkylamino; and R⁵ represents C₁₋₆ alkyl, or a pharmaceutically-acceptable salt thereof.
 2. A compound as claimed in claim 1, wherein the dotted line does not signify a double bond.
 3. A compound as claimed in claim 1, wherein X₁ represents or —C(R^(1a))(R^(1b))— or —N(R^(1a))—.
 4. A compound as claimed in claim 3, wherein X₁ represents —CH₂— or —N(CH₃)—.
 5. A compound as claimed in claim 1, wherein X₂ represents —O—, —N(R^(1e))— or —C(R^(1c))(R^(1d))—.
 6. A compound as claimed in claim 5, wherein X₂ represents —CH₂—.
 7. A compound as claimed in claim 1, wherein X₃ represents —O—, —C(R^(1f))(R^(1g))—C(R^(1h))(R^(1j))—, —C(R^(1c))(R^(1d))— or —C(O)—.
 8. A compound as claimed in claim 7, wherein X₃ represents —CH₂— or —C(O)—.
 9. A compound as claimed in claim 1, wherein A represents —CH₂—.
 10. A compound as claimed in claim 1, wherein Y₁, Y₂, Y₃ and Y₄ all represent —CH—.
 11. A compound as claimed in claim 1, wherein R³ represents C₁₋₄ alkyl.
 12. A compound as claimed in claim 11, wherein R³ represents iso-butyl.
 13. A compound as claimed in claim 1, wherein, when R² represents —S(O)₂N(H)C(O)R⁴, —S(O)₂N(H)S(O)₂R⁴ or —C(O)N(H)S(O)₂R⁴, R⁴ represents n-butoxymethyl, iso-butoxy or n-butoxy.
 14. A compound as claimed in claim 1, wherein R² represents —S(O)₂N(H)C(O)R⁴.
 15. A compound as claimed in claim 14, wherein R⁴ represents n-butoxymethyl, iso-butoxy or n-butoxy.
 16. A compound as claimed in claim 13, wherein R⁴ represents n-butoxy.
 17. A pharmaceutical formulation including a compound as defined in claim 1, or a pharmaceutically acceptable salt thereof, in admixture with a pharmaceutically acceptable adjuvant, diluent or carrier.
 18. A pharmaceutical formulation comprising a compound as defined in claim 1, or a pharmaceutically acceptable salt thereof, and an AT1 receptor antagonist, in admixture with a pharmaceutically-acceptable adjuvant, diluent or carrier.
 19. A kit of parts comprising components: (a) a pharmaceutical formulation comprising a compound as defined in claim 1, or a pharmaceutically acceptable salt thereof, in admixture with a pharmaceutically-acceptable adjuvant, diluent or carrier; and (b) a pharmaceutical formulation comprising an AT1 receptor antagonist, in admixture with a pharmaceutically-acceptable adjuvant, diluent or carrier, which components (a) and (b) are each provided in a form that is suitable for administration in conjunction with the other.
 20. A process for the preparation of a compound as defined in claim 1, which comprises: (i) for compounds of formula I in which R² represents —S(O)₂N(H)C(O)R⁴ or —S(O)₂N(H)S(O)₂R⁴, and R⁴ is as defined in claim 1, reaction of a compound of formula II,

wherein the dotted line, X₁, X₂, X₃, A, Y₁, Y₂, Y₃, Y₄, Z₁, Z₂ and R³ are as defined in claim 1 with a compound of formula III, R⁴GL¹  III wherein G represents —C(O)— or —S(O)₂— (as appropriate), L¹ represents a suitable leaving group and R⁴ is as defined in claim 1; (ii) for compounds of formula I in which R² represents —S(O)₂N(H)C(O)R⁴ and R⁴ represents C₁₋₆ alkoxy-C₁₋₆-alkyl, coupling of a compound of formula II as defined above with a compound of formula IV, R^(4a)CO₂H  IV wherein R^(4a) represents C₁₋₆ alkoxy-C₁₋₆-alkyl; (iii) for compounds of formula I in which R² represents —C(O)N(H)S(O)₂R⁴ and R⁴ is as defined in claim 1, coupling of a compound of formula V,

wherein the dotted line, X₁, X₂, X₃, A, Y₁, Y₂, Y₃, Y₄, Z₁, Z₂ and R³ are as defined in claim 1 with a compound of formula VI, R⁴S(O)₂NH₂  VI wherein R⁴ is as defined in claim 1; (iv) for compounds of formula I in which R² represents —C(O)N(H)S(O)₂R⁴ and R⁴ is as defined in claim 1, coupling of a compound of formula VII,

wherein the dotted line, X₁, X₂, X₃, A, Y₁, Y₂, Y₃, Y₄, Z₁, Z₂ and R³ are as defined in claim 1 with a compound of formula VIII, R⁴S(O)₂Cl  VIII wherein R⁴ is as defined in claim 1; (v) for compounds of formula I in which R² represents —N(H)S(O)₂N(H)C(O)R⁵ and R⁵ is as defined in claim 1, reaction of a compound of formula IX,

wherein the dotted line, X₁, X₂, X₃, A, Y₁, Y₂, Y₃, Y₄, Z₁, Z₂ and R³ are as defined in claim 1 with a compound of formula X, R⁵C(O)N(H)S(O)₂Cl  X wherein R⁵ is as defined in claim 1; (vi) for compounds of formula I in which R² represents —N(H)C(O)N(H)S(O)₂R⁵ and R⁵ is as defined in claim 1, reaction of a compound of formula IX as defined above with a compound of formula XI, R⁵S(O)₂N(H)C(O)R^(x)  XI wherein R^(x) represents a suitable leaving group and R⁵ is as defined in claim 1; (vii) for compounds of formula I in which R² represents —N(H)C(O)N(H)S(O)₂R⁵ and R⁵ is as defined in claim 1, reaction of a compound of formula IX as defined above with a compound of formula XII, R⁵S(O)₂NCO  XII wherein R⁵ is as defined in claim 1; (viii) for compounds of formula I in which R² represents —S(O)₂N(H)C(O)R⁴ and R⁴ represents C₁₋₆ alkylamino, reaction of a compound of formula II as defined above with a compound of formula XIII, R^(4b)NCO  XIII wherein R^(4b) is C₁₋₆ alkyl; or (ix) for compounds of formula I in which R² represents —S(O)₂N(H)C(O)R⁴ and R⁴ represents di-C₁₋₆ alkylamino, reaction of a corresponding compound of formula I in which R² represents —S(O)₂N(H)C(O)R⁴ and R⁴ represents C₁₋₆ alkoxy with a compound of formula XIV, R^(4c)N(H)R^(4d)  XIV wherein R^(4c) and R^(4d) independently represent C₁₋₆ alkyl. 